Average lifespan for Fedora is 4~6 months, for CentOS it's 5~7 years. CentOS is built on the RedHat Enterprise Server source rpms and as such is an enterprise level operating system and ideal for productions servers including web servers as it offers stability and security. Fedora Core is for bleeding edge developers who don't mind having to upgrade their OS every 4 months - by definition it is less secure and certainly less stable and therefore a poor choice for production linux servers:http://fedora.redhat.com/about/rhel.html